Admin Can Specify in Which AWS Availability Zone(s) a PV Shall Be Created

An admin wants to specify in which AWS availability zone(s) users may create persistent volumes using dynamic provisioning.

That's why the admin can now configure in StorageClass object a comma separated list of zones. Dynamically created PVs for PVCs that use the StorageClass are created in one of the configured zones.

examples/persistent-volume-provisioning/README.md

@@ -25,12 +25,13 @@ metadata:
 provisioner: kubernetes.io/aws-ebs
 parameters:
   type: io1
-  zone: us-east-1d
+  zones: us-east-1d, us-east-1c
   iopsPerGB: "10"
 ```
 
 * `type`: `io1`, `gp2`, `sc1`, `st1`. See AWS docs for details. Default: `gp2`.
-* `zone`: AWS zone. If not specified, a random zone from those where Kubernetes cluster has a node is chosen.
+* `zone`: AWS zone. If neither zone nor zones is specified, volumes are generally round-robin-ed across all active zones where Kubernetes cluster has a node. Note: zone and zones parameters must not be used at the same time.
+* `zones`: a comma separated list of AWS zone(s). If neither zone nor zones is specified, volumes are generally round-robin-ed across all active zones where Kubernetes cluster has a node. Note: zone and zones parameters must not be used at the same time.
 * `iopsPerGB`: only for `io1` volumes. I/O operations per second per GiB. AWS volume plugin multiplies this with size of requested volume to compute IOPS of the volume and caps it at 20 000 IOPS (maximum supported by AWS, see AWS docs).
 * `encrypted`: denotes whether the EBS volume should be encrypted or not. Valid values are `true` or `false`.
 * `kmsKeyId`: optional. The full Amazon Resource Name of the key to use when encrypting the volume. If none is supplied but `encrypted` is true, a key is generated by AWS. See AWS docs for valid ARN value.

pkg/cloudprovider/providers/aws/aws.go

@@ -287,11 +287,14 @@ const (
 
 // VolumeOptions specifies capacity and tags for a volume.
 type VolumeOptions struct {
-	CapacityGB       int
-	Tags             map[string]string
-	PVCName          string
-	VolumeType       string
-	AvailabilityZone string
+	CapacityGB        int
+	Tags              map[string]string
+	PVCName           string
+	VolumeType        string
+	ZonePresent       bool
+	ZonesPresent      bool
+	AvailabilityZone  string
+	AvailabilityZones string
 	// IOPSPerGB x CapacityGB will give total IOPS of the volume to create.
 	// Calculated total IOPS will be capped at MaxTotalIOPS.
 	IOPSPerGB int
@@ -1675,10 +1678,23 @@ func (c *Cloud) CreateDisk(volumeOptions *VolumeOptions) (KubernetesVolumeID, er
 		return "", fmt.Errorf("error querying for all zones: %v", err)
 	}
 
-	createAZ := volumeOptions.AvailabilityZone
-	if createAZ == "" {
+	var createAZ string
+	if !volumeOptions.ZonePresent && !volumeOptions.ZonesPresent {
 		createAZ = volume.ChooseZoneForVolume(allZones, volumeOptions.PVCName)
 	}
+	if !volumeOptions.ZonePresent && volumeOptions.ZonesPresent {
+		if adminSetOfZones, err := volume.ZonesToSet(volumeOptions.AvailabilityZones); err != nil {
+			return "", err
+		} else {
+			createAZ = volume.ChooseZoneForVolume(adminSetOfZones, volumeOptions.PVCName)
+		}
+	}
+	if volumeOptions.ZonePresent && !volumeOptions.ZonesPresent {
+		if err := volume.ValidateZone(volumeOptions.AvailabilityZone); err != nil {
+			return "", err
+		}
+		createAZ = volumeOptions.AvailabilityZone
+	}
 
 	var createType string
 	var iops int64

pkg/volume/aws_ebs/aws_util.go

@@ -91,12 +91,18 @@ func (util *AWSDiskUtil) CreateVolume(c *awsElasticBlockStoreProvisioner) (aws.K
 	}
 	// Apply Parameters (case-insensitive). We leave validation of
 	// the values to the cloud provider.
+	volumeOptions.ZonePresent = false
+	volumeOptions.ZonesPresent = false
 	for k, v := range c.options.Parameters {
 		switch strings.ToLower(k) {
 		case "type":
 			volumeOptions.VolumeType = v
 		case "zone":
+			volumeOptions.ZonePresent = true
 			volumeOptions.AvailabilityZone = v
+		case "zones":
+			volumeOptions.ZonesPresent = true
+			volumeOptions.AvailabilityZones = v
 		case "iopspergb":
 			volumeOptions.IOPSPerGB, err = strconv.Atoi(v)
 			if err != nil {
@@ -114,6 +120,10 @@ func (util *AWSDiskUtil) CreateVolume(c *awsElasticBlockStoreProvisioner) (aws.K
 		}
 	}
 
+	if volumeOptions.ZonePresent && volumeOptions.ZonesPresent {
+		return "", 0, nil, fmt.Errorf("both zone and zones StorageClass parameters must not be used at the same time")
+	}
+
 	// TODO: implement PVC.Selector parsing
 	if c.options.PVC.Spec.Selector != nil {
 		return "", 0, nil, fmt.Errorf("claim.Spec.Selector is not supported for dynamic provisioning on AWS")